Facile fabrication of nanofibrous ion-exchange chromatography membrane with aminated surface for highly efficient RNA separation and purification

Construction of ion-exchange chromatography membrane with appropriate pore size and high-density ligands is essential to improve its working efficiency and service life for the separation and purification of biomacromolecules such as RNA . Herein, surface aminated ethylene vinyl alcohol copolymer (EVOH) ion-exchange chromatography nanofibrous membrane (PEI-NFM) with 0.7 µm pore size was fabricated by sea-island spinning and in situ crosslinking (EVOH nanofibers reacted with glutaraldehyde (GA) and polyethyleneimine (PEI) in dispersion). Morphological and chemical characterization of PEI-NFM indicated that GA and PEI crosslinked on the surface of nanofibers uniformly. Benefiting from the 3D network scaffold structure stacked by nanofibers and high-density amine groups, PEI-NFM exhibits high saturated capacity toward RNA (191.16 mg/g), and still possesses more than 93% of its initial adsorption capacity after ten times cyclic adsorption-elution. Moreover, PEI-NFM packed syringe-driven filter shows high water flux of 10.38 L/h at 0.1 MPa and a high dynamic adsorption performance toward RNA (144.07 mg/g at 1 mm/min). Besides, PEI-NFM exhibits high-recognition binding property toward RNA mixed with other biomacromolecules by adjusting pH of mixed solution to make other biomacromolecules positively charged. This work provides a facile strategy for the preparation of high performance and long service life ion-exchange chromatography membrane.